How to Kill Common Dandelion in St. Augustinegrass Without Hurting Your Lawn
Direct Agronomic Answer
To selectively kill Common Dandelion in St. Augustinegrass without damaging your turf, apply Celsius WG (Thiencarbazone-methyl 8.7%, Iodosulfuron-methyl-sodium 1.9%, Dicamba 57.4%) when air temperatures are between 65°F and 95°F.
Because Dandelions store massive carbohydrate reserves in a fleshy taproot up to 10 inches deep, contact herbicides only burn the foliage. Systemic auxin herbicides translocate to the root crown within 72 hours. For sensitive St. Augustine and Centipede lawns that cannot tolerate 2,4-D in summer heat, use Celsius WG between 65°F and 95°F.
1. Labeled Safe Herbicides That Kill Common Dandelion in St. Augustinegrass
| Recommended Product | Active Ingredient & Group | Application Temp (°F) | Surfactant & Mixing Protocol | Where to Buy |
|---|---|---|---|---|
| Celsius WG EPA Reg. 432-1507 |
Thiencarbazone-methyl 8.7%, Iodosulfuron-methyl-sodium 1.9%, Dicamba 57.4% Group 2 + Group 4 (ALS Inhibitors + Benzoic Acid Auxin) |
65°F – 95°F Rainfast: 4h |
Apply with Non-Ionic Surfactant (NIS) at 1 tsp per gallon of water. Specifically engineered not to stunt warm-season turf during summer heat up to 95°F. | Check Price at DoMyOwn View on Amazon |
2. What NOT to Spray on St. Augustinegrass When Treating Common Dandelion
Warning: Common Common Dandelion Killers That Damage St. Augustinegrass
Many retail herbicides advertised for Common Dandelion are formulated for different turf zones and will severely injure St. Augustinegrass:
- AVOID Tenacity (Mesotrione 40%): Rated 'sod_production_only' on St. Augustinegrass — high risk of turf phytotoxicity or stunting.
- AVOID Drive XLR8 (Quinclorac 18.92%): Rated 'avoid' on St. Augustinegrass — high risk of turf phytotoxicity or stunting.
- AVOID SpeedZone Lawn Weed Killer (2,4-D 28.57%, Mecoprop-p 5.88%, Dicamba 1.71%, Carfentrazone-ethyl 0.62%): Rated 'avoid' on St. Augustinegrass — high risk of turf phytotoxicity or stunting.
- AVOID TZone SE (Triclopyr 7.72%, 2,4-D 29.36%, Dicamba 2.22%, Sulfentrazone 0.66%): Rated 'avoid' on St. Augustinegrass — high risk of turf phytotoxicity or stunting.
- AVOID Pylex Herbicide (Topramezone 29.7%): Rated 'avoid' on St. Augustinegrass — high risk of turf phytotoxicity or stunting.
3. Optimal Seasonal Timing & Temperature Thresholds
Spray Dandelions in mid-autumn (October to November) when daytime temperatures are 50°F–75°F and plants actively pump foliar sugars downward into their taproots before winter dormancy.
A secondary application window occurs in early spring during the yellow bud stage before white seed puffballs form. Avoid mowing 2 days before and 2 days after spraying to maximize leaf surface absorption.
4. Diagnostic Checklist: Confirm It Is Common Dandelion Before Spraying
- Deeply notched, tooth-shaped basal leaves pointing backward toward the central crown
- Hollow, leafless flower stalks that exude milky white latex sap when snapped
- Bright yellow composite flower heads maturing into spherical white puffballs of wind-borne achenes
Not 100% sure? Use our AI Photo Weed Scanner or review the full Common Dandelion Botanical Profile.